This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Cognitive deficits occur in Parkinson's disease (PD) and the cause is currently unknown. We propose a novel study utilizing multi-tracer positron emission tomography imaging to investigate the pathophysiology of cognitive impairment in non-demented PD patients. We hypothesize that aggregated protein deposits associated with Lewy body in the cortical regions may correlate with abnormal metabolic activity and underlie cognitive dysfunction.